Portable percussive tool



Filed April 16,l 1943 @ement E; Gosslirg www?.

stalling the motor.

Patented Feb. 8, 1944 e 2,341,433Il PORTABLE PERCUS SIVE TOOL Clement E. Gossling, Toronto, Ontario, Canada, assigner to Rogers Majestic Corporation, Dover, Del., a corporation of Delaware Application April 16, 1943, Serial No. 483,235 In Canada July 14, 1942 (Cl. 12S- 33) 4 Claims.

My invention relates topercussive tools and more particularly to such tools which while power operated are portable.

From time to time a number oi portable tools used for operations requiring percussive and impact motions have been suggested and in fact, marketed. The majority of these were electrically driven and were intended for duties where compressed air was not available. At the present, compressed air driven percussive tools are more suitable for heavier work such as heavy riveting and the like due to the fact that it is not possible to carry in the hand an electic motor of sulcient power for the heavy work intended. There are, however, many applications of a lighter nature, particularly in the building trades for electrically operated portable percussive tools, but the majority of such tools denitely fail to meet all the requirements necessary to achieve full efficiency. To be fully effective they must deal a fast blow which must bevobtained with the greatest possible eiciency and the actual striking element must be of the simplest possible geometric form. Oil lubrication of any kind must be eliminated because of the oil retention diiculties in portable apparatus which receives little or no attention. The mechanism must be immune from the effects of bounce on the part of the tool or overfeed oi the tool, and should the tool jam on the in position, the mechanism mustbe able to function continuously without The actual moving mechanisin must stay, at all times, in driving contact with the motor so as to positively overcome inertia elects. All the mechanism to operate eiciently and eiectively must be of a purely rotary character, and, needless to say, of light weight. The mechanism should, if possible, strike the shank of the tool directly as the interposition of any form of transmitter or socket seriously reduces the value of the blow, as much as 75% oi the blow effect being lost if any space is left between the tool shank and the socket.

One of the principal objects contemplated by my invention comprises producing a portable percussive tool which, while simple and rugged in design and construction, achieves eiectively all of the above noted desired features.

Another object contemplated by my invention comprises producing a portable percussive tool in which the operating principle is such that accuracy of workmanship in the construction ci the tool is not essential.

A still further object contemplated by my invention comprises producing a portable percussive tool of such nature that the tool may be made in sizes varying from those suitable for the lightest type of work to those approaching the limits of portability without material change in the design and operating principle.

I accomplish all of the above noted desirable features and others which will hereinafter become apparent by means of the novel construction, arrangement and interaction of parts which will be hereinafter more specifically described with particular reference to the accompanying drawing forming a part of this specification.

In the drawing which illustrates partially in section land by way of example, one embodiment of my invention, the operating mechanism is enclosed within a housing the portion I of which contains the electric motor 5 and is provided With a hand grip 2. A trigger switch 3 is conveniently located near the grip for control of the motor 5, and a cover plate 30 secured by screw as shown permits access to the switch for assembly purposes and for connecting the conductor 29 to the switch and motor. The motor shaft t is provided with a ball bearing 3 carried by a casting 22 which in turn is carried by the other portion 21 of the housing, The motor shaft 6 is further provided with a pinion gear 1. This pinion gear meshes with a spur gear I8 carried on shaft I2, the axis of which is parallel with the axis of shaft 6 and which is carried in ball bearings 9 and I I. The spur gear IJ is keyed or fixed in any usual to the shaft I2. The shaft I2 and the bearings therefore are retained in the casting 22 by means of the annular cap 2l and cap screws as 2U. The shaft I 2 is in form a Z shaft with a portion thereof I3 offset or bent at an angle to the axis of rotation of the shaft I2. This offset portion I3 carries the offset shaft I4 which carries the hammer member I5. The hammer member I5 is mounted on a metal sleeve I6 by means of a rubber sleeve I1 and is held in limited outward position by means of screw I8. The hammer member I5 is free to rotate on the offset shaft I4 and also free to slide thereon being retained in its upper limit position by means of compression spring 2B. The tool 23 which may be a rivet setting tool, chisel or drive drill, depending upon the Work which it is desired to perform, is carried in a sleeve 25 in the nose of the housing member 21, the sleeve being retained in position by means of the nut 26. The tool 23 is provided with a collar 24 to limit its backward motion toward the hammer member I5. Cap screws as I9 serve to join the housing members I and 21 clamping therebetween the housing separating member 3 I,

It will be observed that when the motor rotates the shaft 6, the shaft I2 is rotated to carry the hammer member I5 into the position shown in the dotted lines wherein once per revolution the bevelled edge of the hammer member I5 is brought into sharp percussive contact with the head of tool 23. It will be observed that the hammer member face is bevelled so as to present a surface which, upon impact with the tool 23, A

is normal to the longitudinal axis of the tool. It; will also be observed that as the hammer member I5 is free to revolve and slide on the offset shaft I4, a new face of the hammer member will each time be brought into contact with the 'tool 23 thereby distributing the wear on the hammer member and providing a long life therefore. It will be observed that this novel design is simple, effective, and rugged, thatJ it permits a fast blow to be struck without any friction effects other than rolling friction, that no transmitter is used, and the tool is struck 'directly by the hammer, that bounce is not detrimental to the mechanism as the striking member can retreat along the offset shaft I4 against the pressure of springs 28. It will be observed that overfeed of the tool would have the same effect as bounce and, therefore, that the motor would continue to drive the tool merely compressing the spring 28 to and fro in the process.

It will be further observed that grease only need be used for the gearing, that no lubrication of any kind is required for the striking mechanism. It will be further noted that the striking element is of the simplest possible construction and accuracy of workmanship is not at all critical. It is immaterial whether the striking member is a good or a bad fit on its supporting Shaft, and that the angle of the offset shaft with re spect to shaft I2 is by no means critical and may be chosen within wide ranges to suit the particular work for which the tool is designed. It should also be noted that this simple, effective design can be followed closely without material change in producing tools from the small sizes suitable for light work to the very large sizes approaching the limit of portability.

While I have thus illustrated and described, by way of example, one complete embodiment of my invention, it will be apparent that many changes may be made therein without departure from the intended scope and spirit of the invention. I do not, therefore, desire to limit myself to the foregoing except as'may be pointed out in the appended claims in which I claim and desire to secure by United States Letters Patent the following:

1. A portable percussive 'tool comprising, a housing, a shaft carried by said housing, means carried by said housing for driving said shaft, said shaft having a portion near one extremity thereof bent to extend at an angle of less than '90 with the axis of rotation of said shaft, a pinion carriedby said bent portion with the axis of said pinion at 90 to the axis of said bent portion, a hammer member rotatively carried by said pinion and a tool carried by said housing and so positioned relative to said hammer member as to receive therefrom a blow driving said tool in the direction of its longitudinal axis once during each rotation of said shaft.

2. A portable percussive tool comprising, a housing provided with a hand-grip, a shaft carried by said housing, means within said housing for driving said shaft, said shaft having a portion near one extremity thereof bent to extend at an angle of less than to the axis of rotation of said shaft, a pinion carried by said bent portion with the axis of said pinion at 90l to the axis of said bent portion, a circular hammer member rotatively and slidably mounted on said pinion and a tool carried by said housing and so positioned relative to said hammer member as to receive therefrom a blow driving said tool in the direction of its longitudinal axis once during each rotation of said shaft.

3. A portable percussive Ytool comprising, a housing provided with a hand-grip, a rst shaft carried by said housing, means within said housing for driving said shaft, 'a second shaft carried -by said housing, means whereby said second shaft is driven by said first shaft, said second shaft having a portion near one extremity thereof bent to extend at an angle yof less than y90" to the axis of rotation of said second shaft, a pinion carried by said bent portion `with Athe axis of said pinion at 90 to the axis of said bent portion, a hammer member rotatively and slidably mounted on said pinion,la spring carried between lsaid hammer member and said bent portion of said second shaft for taking up the rebound of said hammer member and a tool'car.- ried by said housing and vso positioned relative to said hammer member as to receive therefrom a blow driving said tool inthe direction of its longitudinal axis once during each rotation of said second shaft.

4. A portable percussive tool comprising, a housing provided with a hand-grip, a first shaft carried by said housing, means within said housing-for driving said shaft, a second shaft carried by said housing, means whereby said second shaft is driven by said first shaft, said second shaft having a lportion near one extremity `thereof bent to extend at an angle of less than 90 to the 'axis of rotation of said second shaft, a pinion carried by said bent portion with the yaxis of said pinion at 90 to the axis of said bent portion, a circular hammer rmember rotatively and slidably mounted on said pinion, resilient means between the bent portion of said second shaft and said hammer member, a spring carried between said hammer member and the bent -portion of said second shaft for taking up the rebound of said hammer member and a tool carried by said housing and so positioned relative to said hammer member as-to receive therefrom a blow driving said tool in the direction ofits longitudinal axis once during each rotation'of said second shaft.

CLEIVIENT E. GOSSLING. 

